The present invention is in the field of liquid or gel detergents. More specifically, the invention relates to sprayable liquid detergents which provide enhanced cleaning, e.g. improved stain removal on plastics, fabrics, and other substrates. These cleaning compositions comprise a bleaching agent, preferably diacyl peroxide, which is stabilized in a liquid or gel detergent formulation.
Detergents used for washing tableware (i.e., glassware, china, silverware, plastic, etc.) or kitchenware in the home or institutional especially designed for the purpose have long been known. Dishwashing in the seventies is reviewed by Mizuno in Vol. 5, Part III of the Surfactant Science Series, Ed. W. G. Cutler and R. C. Davis, Marcel Dekker, N.Y., 1973, incorporated by reference. The particular requirements of cleansing tableware and leaving it in a sanitary, essentially stainless, residue-free state has indeed resulted in so many particular compositions that the body of art pertaining thereto is now recognized as quite distinct from other cleansing product art. Additionally, the body of art pertaining to fabric cleaning is immense and encompasses many formulations designed for stain removal, many including bleaches.
However, consumers continue to experience problems with stain removal on various substrates, including typical kitchenware surfaces and fabrics. In particular, formulators have experienced difficulties in formulating detergents which remove both hydrophobic and hydrophilic stains. Typically for stain removal, formulators have turned to chlorine bleach or sources of hydrogen peroxide and bleach activators.
Numerous substances have been disclosed in the art as effective bleach activators. One widely-used bleach activator is tetraacetyl ethylene diamine (TAED). TAED provides effective hydrophilic cleaning especially on beverage stains, but has limited performance on dingy stains and body soils. Another type of activator, such as nonanoyloxybenzenesulfonate (NOBS) and other activators which generally comprise long chain alkyl moieties, is hydrophobic in nature and provides excellent performance on dingy stains.
It would seem that a combination of bleach activators, such as TAED and NOBS, would provide an effective detergent composition which would perform well on both hydrophilic and hydrophobic soils and stains. However, many of the hydrophilic activators developed thus far, including TAED, have been found to have limited efficacy, especially at laundry liquor temperatures below 60xc2x0 C. Another consideration in the development of consumer products effective on both types of soils is the additional costs associated with the inclusion of two or more bleach activators. Accordingly, it is of substantial interest to the manufacturers of bleaching systems to find a less expensive type of hydrophilic bleaching activator.
Chlorine bleaches are effective for stain and/or soil removal. While chlorine bleach is a very effective cleaning agent, it is not compatible with a variety of detergent ingredients and may require lengthy soaking time in which the bleach and the stained substrate must remain in contact to ensure stain removal.
Another known bleaching source is diacyl peroxides (DAPs). Although DAPs have been disclosed for use in the laundry and anti-acne area, they have had limited success in liquid or automatic dishwashing detergent area. In the laundry field certain diacyl peroxides have been disclosed as beneficial in cleaning tea stains from fibrous material. It has now been discovered that DAPs can improve stain removal performance on plastics.
Another problem facing formulators is stability of the bleaching agents and other individual ingredients over time, especially in liquid products. This is particularly true for diacyl peroxides in alkaline conditions.
As a consequence to the above-identified problems, there has been a substantial amount of research to develop bleaching systems which are stable and effective in liquid formulations and in which the amount of soaking time needed to remove stains is greatly reduced.
By the present invention, it has now been discovered that certain bleaching agents when combined with surfactants, and clay thickeners are stable and perform very well on stains and has the added benefit of being relatively inexpensive to manufacture. Accordingly, the present invention solves the long-standing need for an inexpensive bleaching system which performs efficiently and effectively at low temperatures and under mixed soil load conditions, especially mixtures of hydrophobic and hydrophilic soils.
The novel detergent compositions provided herein have the property of removing stains, especially tea, fruit juice and carotenoid stains objected to by the consumer from plastic dishware, glass, wood, fabric, and many other known substrates. The compositions have other cleaning benefits in addition to stain removal advantages such as deodorizing and disinfecting. Sprayable liquid or sprayable gel detergent compositions are provided for powerful cleaning of wide-ranging stains on a wide-variety of substrates while retaining the advantages of a stable, mild product matrix.
The present invention encompasses sprayable liquid or gel detergent compositions especially effective at cleaning stains from fabrics, dentures, surgical/medical equipment, baby bottles, dishes, kitchenware, and/or other substrates, comprising by weight:
(a) from about 0.1% to about 60%, preferably 0.1 to about 40%, more preferfbly from about 0.3% to about 10%, of a bleaching agent selected from the group consisting of:
i) diacyl peroxide having the general formula:
RC(O)OO(O)CR1
xe2x80x83wherein R and R1 can be the same or different and are hydrocaryls, preferably no more than one is a hydrocarbyl chain of longer than ten carbon atoms, more preferably at least one has an aromatic nucleus;
ii) a source of hydrogen peroxide;
iii) a source of hydrogen peroxide and a bleach activator;
iv) a chlorine bleach, preferably hypochlorite; and
v) mixtures thereof;
(b) from 0% to about 95% of a solvent;
(c) from 0% to about 50%, preferably from about 2% to about 45%, more preferably from about 8% to about 40% of a surfactant; and
(d) from 0% to about 7%, preferably from about 0.5% to about 5%, more preferably from about 0.75% to about 3%, of a thickener, especially Laponite(copyright); and the balance water.
Said compositions also are effective at deodorizing and disinfecting said substrates.
For compositions which provide both stain removal and tough food cleaning, solvents are preferably not present. Without being limited by theory, it is believed that the presence of solvents may act to dissolve the diacyl peroxide and thus reduce the abrasive character of the composition. Thus, for an abrasive, tough food cleaning formulation, it is preferable that the solvent be limited to no more than about 4%, more preferably no more than about 2%, by weight of the composition.
For sprayable compositions, solvent may be present with any of the above identified bleaching agents. However, when diacyl peroxide is present as the bleaching agent, it is preferable to have from about 2% to about 80% of a solvent capable of dissolving the diacyl peroxide. Suitable solvents are preferably selected from the group consisting of N-alkyl pyrrolidones, such as N-ethyl pyrrolidone, diacetone alcohol, alkyl ethers, cyclic alkyl ketones, and mixtures thereof. Amines, ethers and low molecular weight primary and secondary alcohols (about C1-C6) are preferably not present. Without being limited by theory, it is believed that the presence of these compounds may introduce stability problems. Thus, when diacyl peroxide and solvent are present in the compositions of this invention, it is further preferable that the amount of amine, ether, or primary or secondary alcohol be limited to no more than about 5%, preferably no more than about 3%, by weight of the composition.
The invention optionally comprises a thickener which may be selected from clay thickeners or polycarboxylate, especially Polygel(copyright) thickeners, polyacrylates, carboxymethyl cellulose, gums, and mixtures thereof.
Said cleaning composition is preferably sprayed onto said substrate. It is preferable to allow said composition to remain in contact with said substrate for a sufficient period of time (from about 1 minute to about 3 hours, more preferably from about 1 hour to about 2 hours) to clean, remove or reduce stains and soils, deodorize or disinfect the substrate.
In another method herein, the substrate is contacted by the cleaning composition and then subjected to microwaving for a sufficient time (preferably from about 1 second to about 2 minutes, more preferably from about 10 seconds to about 45 seconds) to clean, remove or reduce the stains and soils, deodorize or disinfect said substrate. If microwaving, water should also be present. The substrate may be wetted or dampened by water before or after application of the bleaching composition. Preferably, the bleaching composition comprises water. The compositions herein may, therefore, additionally comprise from about 0.1% to about 99.5%, more preferably from about 60-95%, even more preferably from about 80% to about 95%, by weight of the composition of water.
All percentages and proportions herein are by weight, and all references cited are hereby incorporated by reference, unless otherwise specifically indicated.